Topic 5 - Early Human Development Flashcards Preview

Anatomy > Topic 5 - Early Human Development > Flashcards

Flashcards in Topic 5 - Early Human Development Deck (48):
1

How many weeks is the pre-embryonic period and when?

first 2 weeks

2

What is part of the pre-embryonic period?

 

  1. Zygote
  2. Morula
  3. Blastocyst

3

Zygote

  • how many cells?
  • diploid or haploid?

  • 1 cell
  • Diploid

4

What does the Zygote undergo?

undergoes rapid mitotic divisions called cleavage divisions

5

what are cleavage divisions?

rapid mitotic divisions

6

Morula

how many hours?

72

7

Morula

  • describe its physical appearance
    • how many cells? what are the cells called?
    • same size as what?

  • solid ball of 16-32 cells (Cells called blastomeres)
  • SAME size as ovum/zygote

8

what is the same size as a zygote?

morula

9

Blastocyst

how long is the duration?

5 days

10

Describe the blastocyst

  • fluid filled cavity develops = blastocoel/blastocyst cavity
  • inner cell mass
  • trophoblast (made of trophoblast cells)

11

go into detail about the inner cell mass of the blastocyst

cells divide and differentiate (undergo changes to

become more specialized) to form the embryo 

12

go into detail about the trophoblast of the blastocyst

cells will divide and differentiate to form chorion - provides nutrients to developing embryo 

13

what does the blastocyst do?

  • moves from where?
  • attaches to what?
  • what is that called?
  • how many days after ______?

blastocyst moves from uterine tube and attaches to endometrium of uterine wall = implantation

5 - 7 days after fertilization

14

describe the blastocyst after implantation

 

  • inner cell mass forms a 1 layered (bilayered) embryonic disc composed of:
    • epiblast
    • hypoblast

15

epiblast

will undergo mitosis to form

  1. amnion - with a fluid filled amniotic cavity
  2. 3 germ layers of the embryo

16

hypoblast

will undergo mitosis to form the yolk sac

17

how long is the duration of the Embryonic period?

 

3rd week to the end of the 8th week

18

describe the embryonic period

  • how many layers
  • what does it form?
  • how were the layers formed?

  • 3 germ layers are now present forming the embryo (Each layer was formed from mitosis and differentiation of epiblast cells):
    1. Ectoderm
    2. Mesoderm
    3. Endoderm

19

Ectoderm

what will it form?

will form the nervous system and the epidermis

20

Mesoderm

what will it form?

will form

  1. muscles
  2. cardiovascular system
  3. dermis
  4. most bones

21

Endoderm

what will it form?

  • will form epithelial linings of 
    1. digestive
    2. respiratory
    3. urinary
    4. reproductive systems and their associated glands

22

what happens during the embryonic period?

  1. what happens to the major organ systems?
  2. what happens to the heart?
  3. what happens to the limb buds?
  4. what forms during this period?

 

  1. major organ systems almost completely formed
  2. heart begins to beat
  3. limb buds differentiate
  4. embryonic membranes form

23

what happens during the embryonic period?

  1. major organ systems almost completely formed
  2. heart begins to beat
  3. limb buds differentiate
  4. embryonic membranes form

24

what embryonic membranes are formed?

  1. yolk sac
  2. amnion
  3. allantois
  4. chorion

YAAC

25

chorion

  1. derived from what?
  2. surrounds what?
  3. projections of what? 
  4. what will these projections form?
  5. what are these projections called?

  1. derived from trophoblast
  2. surrounds all embryonic membranes
  3. projections of the chorion containing blood vessels 
  4. that will form fetal part of placents
  5. called chorionic villi

26

what is the chorion derived from?

trophoblast cells

27

derived from trophoblast cells

chorion

28

surrounds all embryonic membranes

chorion

29

projections of the chorion containing the blood vessels that will form fetal part of placenta

chorionic villi

30

amnion 

  1. derived from?
  2. forms what?
  3. which surrounds?...

  1. derived from epiblast
  2. forms amniotic cavity
  3. amniotic cavity surrounds embryo/fetus with amniotic fluid

31

what is the function of the amniotic fluid?

  1. shock absorption
  2. temperature regulation

32

what has this function?

  1. shock absorption
  2. temperature regulation

amniotic fluid of the amnion

33

derived from epiblast

amnion

34

forms amniotic cavity - surrounds embryo/ fetus with amniotic fluid

amnion

35

yolk sac

  1. derived from?
  2. forms?
  3. produces?
  4. source of?

  1. derived from hypoblast
  2. forms part of gut (gastrointestinal tract)
  3. produces earliest blood cells and vessels
  4. source of primordial germ cells (reproductive cells = primary oocytes + primary spermatocytes)

36

derived from hypoblast

yolk sac

37

forms part of gut (gastrointestinal tract)

yolk sac

38

produces earliest blood cells and vessels

yolk sac

39

source of primordial germ cells

yolk sac

40

allantois 

  • what part of the yolk sac?
  • what does it form?

  • out-pocket of yolk sac
  • forms the umbillical cord and the urinary bladder

41

out-pocket of yolk sac

allantois

42

forms the umbilical cord and the urinary bladder

allantois

43

what week does the fetal period begin and end? and what occurs during this period?

  • 9th week to the end of the 40th week
  • growth and maturation of organs occurs

44

9th week to the end of the 40th week

fetal period

45

growth and maturation of organs occurs during this period

fetal period

46

3rd week to end of the 8th week

embryonic period

47

  • major organ systems almost completely formed
  • heart begins to beat
  • limb buds differentiate 
  • embryonic membranes form 

during this period:

embryonic period

48

what provides nutrients to the developing embryo?

chorion